Exam 1 Hu

(in general - not just systemic) different delivery routes

(in general - not just systemic) different delivery routes

•Ocular

•Buccal

•Sublingual

•Oral

•IV

•IM

•Subcu

•Transdermal

•Pulmonary/Nasal

•Vaginal/Rectal

Know the factors to be considered for oral controlled drug delivery.

Drug properties stability, solubility, charge, protein binding

Target sites→maximize drug released at the desired site to reduce side effects

Acute or chronic disease therapy →cure of control? , expected length of drug therapy

The patient→ gender, age, physical conditions diseases ?

Non suitable factors for controlled drug delivery

•Short elim half-life

•Large doses

•Small TI

•Poor absorption

Extensive 1st pass clearance

• Half-life less than 2 hrs

Controlled release (CR)

Delivers drug in a manner that is planned, predictable, and slower than normal

Sustained release (SR)

provides continual delivery in comparison to an immediate release

Delayed release

releases a drug at a time other than promptly after dosing

Targeted release

releases a drug at a specific site

Responsive release

releases drug upon the specific stimulation

Advantages of controlled drug delivery systems

•Increased patient compliance: reduce the frequency of dosing

•Sustained pharmacodynamic response: provide more effective disease treatment, esp for chronic disease states

•Reduce side effects: less “peaks and valleys”

•Enhances bioavailability

disadvantages of controlled drug delivery systems

•Poor in vitro-in vivo correlation bc of physiological environment

•Toxicity due to dose dumping→a lot of drug released at once

•High cost

•Reduced potential for dose adjustment

•Poor systemic availability in general

•Stability problem

Diffusion Control - Matrix systems

•Dispersed in a polymer matrix

•Drug release controlled by diffusion from the matrix

•Rate of release depends on the amount of drug present at a particular time (time-dependent)

Diffusion Control - Membrane reservoirs

•Active drug is in the core surrounded by a polymer membrane

•Drug is released via diffusion

•Diffusion of water through polymer is rate-determining step

•Rate of release is constant and proportional to the initial concern of drug

Polymer Degradation

Drug is contained within polymer membrane and the polymer is designed to degrade and release the drug at a specific location

Solvent Activated

• Semi-permeable membrane with a hole

•High salt concen in membrane causes water to enter → Forces drug out hole bc pressure

•Drug releases at a constant rate

Solvent Activated- swellable gels

Polymeric materials with 3D crosslinked network

The mesh size plays a central role in controling drug release behavior

Solvent Activated- osmotic systems

A carrier covered with a semi permeable polymeric membrane via which water can flow from outside of the carrier to the drug loaded core.

Responsiveness

Drug release controlled by stimuli like pH, temp, sound, electric field, ionic strength,

Know the main mechanisms for stomach-specific drug delivery.

1)Mucoadhesion: Mucoadhesive polymers could theoretically cause a dosage form to adhere to the stomach mucose to retain it in the stomach

2) Floating: The dosage form should float on the stomach contents

3) Size-increasing systems: The dosage form swells and increases in size as soon as it reaches the stomach to avoid being able to pass through

Know the barriers to oral bacteria delivery.

•Resistance to environmental assaults

→ Stomach pH

•Retention in the intestine

→poor absorption

Know the working mechanism of enteric coating and coating materials.

Enteric Coating: Polymers remain intact in acid pH, but once they get into neutral pH thye start degradation

→Eudragit L100

Understand the basic mechanism of fecal microbiota transplantation.

1) Stool is harvested from a healthy donor

2) A fecal sample is transplanted into the intestines of the patient

3) The organisms from the donor restore a healthy gut microbiome in the patient